PHYS 345 |
| Compared to ions of similar charge density and size, the hydroxide ion displays an anomalously fast rate of diffusion in water due to its ability to accept protons from neighboring molecules. The mechanism by which this proton exchange occurs is not yet well understood. We report the results of ultrafast vibrational echo experiments that probe the OH stretch of a solution of dilute HOD dissolved in D2O:NaOD. The frequency of the OH stretch is a sensitive probe of the local environment, shifting with the strength of the hydrogen bond to the proton. With increasing NaOD concentration, three pulse photon echo peakshift measurements indicate the environment surrounding HOD molecules is static up to ~2 ps, suggesting that OD- ions possess a stable solvation shell over this timescale. Moreover, 2D IR measurements display a large off diagonal intensity which is possibly a marker of rapid proton transfer within the OD- solvation shell. |
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PHYS Poster Session - Optical Probes of Dynamics in Complex Environments
7:30 PM-10:00 PM, Wednesday, April 9, 2008 Morial Convention Center -- Hall A, Poster
Division of Physical Chemistry |